Chewing gum packaging formed from laminates is known. The laminates used for gum packaging are designed to minimize the transmission of oxygen and moisture. Conventionally, sticks of chewing gum are packaged in two separate wrappers, an inner wrapper disposed around each individual stick of gum, and an outer wrapper housing a plurality of sticks. The outer wrapper is known in the industry as a counterband.
Some issues facing packagers of chewing gum are discussed in U.S. Pat. No. 5,376,388 to Meyers, which is incorporated herein by reference.
Chewing gum loses or gains moisture from the environment depending on the ambient temperature, humidity, and packaging type. The gain or loss of moisture also depends on the shape and composition of the chewing gum. Chewing gums with sugar generally have corn syrup and a small amount of humectant such as aqueous sorbitol or glycerin. These gums tend to dry out and become brittle when stored in ambient humidity less than 50%. Higher ambient temperatures exasperate the gum's tendency to dry out.
Sugarless gums typically contain lower amounts of moisture than sugar-containing gums. It is particularly important to maintain a low moisture content in sugarless gums which are sweetened with aspartame or other moisture-sensitive artificial sweeteners, thus preventing the loss of flavor. These sugarless gums have a lower initial moisture content and higher level of hygroscopic ingredients than do sugar-containing gums. Thus, sugarless gums tend to gain moisture when exposed to relative humidity above 40%, causing degradation of the moisture-sensitive ingredients.
It is known to package chewing gum in a laminate formed from a tissue or paper substrate that defines an inner surface for contacting the chewing gum and a metal foil outer surface. The metal foil provides resistance to the transmission of both moisture and vapor. This laminate will be referred to as the inner wrapper.
Typically, the inner wrapper does not provide sufficient barrier properties for long term storage of chewing gum. Thus, it is common to house a group of individually wrapped gum sticks in an outer wrapper or counterband. The conventional counterband is a laminate having greater long term resistance to the passage of gas and moisture. A conventional counterband may comprise numerous layers; one known structure being: (1) aluminum foil; (2) polyethylene; (3) paper; (4) adhesive; (5) reverse printed ink; (6) oriented polypropylene; and (7) release over-laquer. The counterband seals and contains the sticks of gum wrapped in their inner wrappers until a consumer tears open the counterband to remove the first stick.
Although the inner wrapper and counterband provide sufficient barrier properties for the long term storage of chewing gum, the system raises a number of issues. The cost of the laminates is one issue. Utilization of multi-layer laminates in place of simple paper webs substantially increases packaging costs. For at least some chewing gums, packaging costs can comprise a substantial portion of the product's overall cost. However, without the use of laminates, the shelf-life of chewing gum would be substantially reduced.
Another issue facing the packagers of gum is the well known problem of slip agent migration. Slip agents, commonly found in laminates, enhance the processing thereof by reducing the coefficient of friction of the laminate as measured against itself and against machine parts across which the laminate may slide during processing. The decreased coefficient of friction allows the laminate to be easily moved across such surfaces without ripping or wrinkling. However, slip agents are prone to migration which can cause delamination of the laminate as well as interference with adhesion of metallized coatings.